Improvement in the processes for softening and toughening blocks of wood



UNITED STATES PATENT OFFIGE.

GEORGE W. SWAN, OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT IN THE PROCESSES FOR SOFTENING AND IOUGHENING BLOCKS 0FWOOD.

Specification forming part of Letters Patent No. 142.298, dated August26, 1873; application filed June 17, 1873.

To all whom it may concern:

' fornia, have invented an Improved Process for Softening and TougheningBlocks of Wood; and I do hereby declare the following descriptionsufficient to enable any person skilled in the art or science to whichit most nearly appertains to make and use my said invention orimprovement without further invention or experiment.

My invention relates to an improved process for softening and tougheningblocks of wood preparatory to cutting them into veneers or boards with aveneer-cutting machine.

Heretofore it has been the practice to either steam the blocks of woodor boil them in hot water before cutting them into veneers, in order tosoften the wood and render it pliable, so that it would not split whilebeing cut. This process, however, would only admit of .the cutting ofvery thin veneers, and in some kinds of wood even this imperfectly.

My process consists in filling the tank half full of hot water, and thenplacing in the water a quantity of ammonia or borax, or both combined,so as to make a strong solution of these substances. The quantity ofthese substances to be employed will be governed by the quantity ofwater in the tank in each case,

no particular quantity being required so long as the solution is madestrong with the chemicals. I then place the blocks of wood in the tankuntil it is filled and the solution covers them, after which I cover thetank closely and introduce steam from a steam-boiler into the bottom ofthe tank, or apply heat to it, as most convenient. The blocks, are thusleft until they become thoroughly saturated and steamed, the length oftime required varying according to the character of the wood.

Blocks prepared in this way can be out into veneers or boards of anydesired thickness without trouble, and will retain their flexibilityafter becoming dry an indefinite length of v time.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

The process of boiling or steaming blocks of wood in a solution ofammonia and borax, substantially as and for the purpose above dcscribed.

In witness whereof I hereunto set my hand and seal.

GEORGE W. SWAN. [L. s.]

Witnesses:

JOHN L. BOONE', 0. M. RICHARDSON.

